1. Field of the Invention
The present invention relates to a human fecal collection system with features which allow it to be used in weightless conditions of space flight.
2. Brief Description of the Prior Art
In the closed and limited volume of current space craft, waste collection, handling, and disposal, further complicated by weightlessness and absence of significant quantities of power and water, is a major health concern. It may also have an emotional impact on the crew, and especially untrained passengers, forced to deal with human waste in a fashion contrary to culture and experience.
The first inflight solid waste collection system was an adhesive rimmed bag stuck on the subject's buttocks with a finger cot molded in for removal of adherent material. Skylab used a seat with an individual, replaceable bag collector, integral filter, and flow through air entrapment system. Individual bags were then vacuum dried and stored for return to earth. Because of the size, complexity and power cost of the Skylab waste collection system, a more efficient system was designed for the space shuttle. This system used a single large pot with a centrifugal macerator/slinger which would plaster the pot walls with successive layers of fecal material, which were subsequently dried by vacuum. There are serious operational difficulties with this system. The personal experience of a co-inventor (an astronaut) of the instant invention during a ground simulation and two space flights with the shuttle waste collection system provided the impetus for the development of the present invention.
A number of patents disclose an array of waste collection devices, many of which are designed for space flight. These patents disclose vacuum and air assist means, bagging means, and sweep means (in the form of bare pistons). However, none of these suggest the concept of a waste collection chamber having a piston acting therein with a replaceable facing material thereon to clean the chamber, compact and separate the materials with each cycling of the piston.
An example of a waste collection system can be found in U.S. Pat. No. 4,281,655 (Trauchi, 1981) which discloses a vacuum suction type urinal designed to conform to body parts. Urine is automatically carried along with air sucked from a urine receiving unit and transmitted to a urinal. Air is supplied to the urine receiving unit through a plurality of small holes. The urine so collected is disposed of by customary means.
An example of a zero gravity toilet with a buttocks-conforming seat is found in U.S. Pat. No. 3,340,544 (Cella, 1967). The seat creates an airtight seal against the subject's buttocks. High pressure fluid is directed through jet means to the subject's anus, thereby washing it clean following use. Positive pressure in the water collection system cavity forces the water down a tube sending it into a low pressure collection receiver. The fluid contains reagents which will form a resin plug in the depending tube. The plug, urged by air pressure, will be forced down the tube and clean the passage as it advances.
U.S. Pat. No. 3,405,409 (Bennett, 1966) discloses a space toilet which includes a vacuum suction means combined with air flow jets located around the periphery of the seat. The vacuum means is used to draw the liquid and solid waste material into a gas permeable collection bag. A second bag encompassing the first is completely impermeable. The first bag is manually sealed by the user within the second bag, and dropped into a continuously heated dessication chamber which is sealed by a piston. The piston is not used to compress, but merely to seal the dessication chamber from the waste collection area, and prevent the escape of odor.
A flush toilet which utilizes positive control over a liquid flushing medium is described in U.S. Pat. No. 3,329,974 (Belasco et al., 1967). A current of air supplied near the seal between the seat and the subject's buttocks, directs both feces and odor to the toilet bowl outlet. A water jet is provided to cleanse the rectal area which is followed by a drying jet of warm air. Water under pressure is used to wash the toilet bowl, and the liquids and feces removed through the bowl outlet are conveyed to a blender. Urine and the feces/water mixture from the mechanical blender are pumped to a vacuum distillation unit. Distilled water from the vacuum distillation unit is then available for future flushing. A continuous low pressure is maintained in the system, preventing the escape of odor into the cabin.
Despite the numerous inventions relating to waste collection and storage, none has yet been developed that efficiently and simply solve the problems encountered in space flight. No previous device has been designed that is compact, simple and efficient, and combines air flow means, piston means, replaceable facing pads, and a storage means.